feat(lsp): use vim.ui.select for selecting lsp client (#16782)

(cherry picked from commit 43cdcba476)

Co-authored-by: Anshuman <amedhi@connect.ust.hk>

runtime/lua/vim/lsp/buf.lua

@@ -116,31 +116,30 @@ end
 --- asks the user to select one.
 --
 ---@returns The client that the user selected or nil
-local function select_client(method)
-  local clients = vim.tbl_values(vim.lsp.buf_get_clients());
-  clients = vim.tbl_filter(function (client)
+local function select_client(method, on_choice)
+  validate {
+    on_choice = { on_choice, 'function', false },
+  }
+  local clients = vim.tbl_values(vim.lsp.buf_get_clients())
+  clients = vim.tbl_filter(function(client)
     return client.supports_method(method)
   end, clients)
   -- better UX when choices are always in the same order (between restarts)
-  table.sort(clients, function (a, b) return a.name < b.name end)
+  table.sort(clients, function(a, b)
+    return a.name < b.name
+  end)
 
   if #clients > 1 then
-    local choices = {}
-    for k,v in pairs(clients) do
-      table.insert(choices, string.format("%d %s", k, v.name))
-    end
-    local user_choice = vim.fn.confirm(
-      "Select a language server:",
-      table.concat(choices, "\n"),
-      0,
-      "Question"
-    )
-    if user_choice == 0 then return nil end
-    return clients[user_choice]
+    vim.ui.select(clients, {
+      prompt = 'Select a language server:',
+      format_item = function(client)
+        return client.name
+      end,
+    }, on_choice)
   elseif #clients < 1 then
-    return nil
+    on_choice(nil)
   else
-    return clients[1]
+    on_choice(clients[1])
   end
 end
 
@@ -152,11 +151,15 @@ end
 --
 ---@see https://microsoft.github.io/language-server-protocol/specification#textDocument_formatting
 function M.formatting(options)
-  local client = select_client("textDocument/formatting")
-  if client == nil then return end
-
   local params = util.make_formatting_params(options)
-  return client.request("textDocument/formatting", params, nil, vim.api.nvim_get_current_buf())
+  local bufnr = vim.api.nvim_get_current_buf()
+  select_client('textDocument/formatting', function(client)
+    if client == nil then
+      return
+    end
+
+    return client.request('textDocument/formatting', params, nil, bufnr)
+  end)
 end
 
 --- Performs |vim.lsp.buf.formatting()| synchronously.
@@ -172,17 +175,20 @@ end
 ---@param timeout_ms (number) Request timeout
 ---@see |vim.lsp.buf.formatting_seq_sync|
 function M.formatting_sync(options, timeout_ms)
-  local client = select_client("textDocument/formatting")
-  if client == nil then return end
-
   local params = util.make_formatting_params(options)
   local bufnr = vim.api.nvim_get_current_buf()
-  local result, err = client.request_sync("textDocument/formatting", params, timeout_ms, bufnr)
-  if result and result.result then
-    util.apply_text_edits(result.result, bufnr)
-  elseif err then
-    vim.notify("vim.lsp.buf.formatting_sync: " .. err, vim.log.levels.WARN)
-  end
+  select_client('textDocument/formatting', function(client)
+    if client == nil then
+      return
+    end
+
+    local result, err = client.request_sync('textDocument/formatting', params, timeout_ms, bufnr)
+    if result and result.result then
+      util.apply_text_edits(result.result, bufnr)
+    elseif err then
+      vim.notify('vim.lsp.buf.formatting_sync: ' .. err, vim.log.levels.WARN)
+    end
+  end)
 end
 
 --- Formats the current buffer by sequentially requesting formatting from attached clients.
@@ -238,12 +244,15 @@ end
 ---@param end_pos ({number, number}, optional) mark-indexed position.
 ---Defaults to the end of the last visual selection.
 function M.range_formatting(options, start_pos, end_pos)
-  local client = select_client("textDocument/rangeFormatting")
-  if client == nil then return end
-
   local params = util.make_given_range_params(start_pos, end_pos)
   params.options = util.make_formatting_params(options).options
-  return client.request("textDocument/rangeFormatting", params)
+  select_client('textDocument/rangeFormatting', function(client)
+    if client == nil then
+      return
+    end
+
+    return client.request('textDocument/rangeFormatting', params)
+  end)
 end
 
 --- Renames all references to the symbol under the cursor.